Interface adhesion potassium ion gel electrolyte and preparation method thereof

Abstract

The invention belongs to the technical field of potassium ion battery materials, and particularly relates to an interface adhesion potassium ion gel electrolyte and a preparation method thereof.The preparation method comprises the steps that azodiisobutyronitrile is added into a potassium ion electrolyte and stirred to be uniform until the azodiisobutyronitrile is dissolved, and an electrolyte precursor is obtained; uniformly mixing butyl acrylate and methyl methacrylate to obtain a gel electrolyte polymer precursor; the electrolyte precursor and the gel electrolyte polymer precursor are uniformly mixed and stirred to prepare a gel electrolyte precursor, and then the gel electrolyte precursor is placed in a mold for thermal polymerization to obtain the interface adhesion potassium ion gel electrolyte. The method is short in production period, low in cost and simple to operate. The prepared interface adhesion potassium ion gel electrolyte has relatively good interface adhesion, potassium metal affinity and ion transmission performance, and can be widely applied to the field of potassium ion batteries.

Description

Technical Field

[0001] The invention belongs to the technical field of potassium ion battery materials, and specifically relates to an interface-adherent potassium ion gel electrolyte and a preparation method thereof. Background Art

[0002] Energy, as the most important core of the new era, plays a vital role in the stable operation of power grids and big data, and requires appropriate energy storage technology. At present, due to the good electrochemical properties of lithium metal, lithium-based lithium-ion batteries occupy a leading position as the main technical means in both energy storage systems and power systems. However, with the rapid development of lithium energy storage systems in recent years, market demand has increased, and further led to a shortage of limited lithium raw materials, resulting in a gradual increase in its cost. Therefore, it is urgent to develop new electrochemical energy storage technologies to alleviate the cost pressure caused by the expansion of lithium-ion battery systems. Potassium metal, which is in the same group as lithium in the periodic table, has similar electrochemical properties to lithium, and has an element reserve of 2.46% in the earth's crust, which is far higher than lithium, and has good application prospects. Most of the existing potassium ion batteries are liquid battery systems based on liquid electrolytes. Due to the generation of dead potassium penetrating the diaphragm during the cycle, it is easy to cause battery short circuit and further cause safety and poor cycle performance. Organic gel electrolytes are simple to prepare and can effectively fix liquid electrolytes, which can alleviate the safety problems of liquid batteries to a certain extent. Summary of the invention

[0003] In order to solve the problems existing in the prior art, the main purpose of the present invention is to provide an interface-adhered potassium ion gel electrolyte and a preparation method thereof.

[0004] According to one aspect of the present invention, the present invention provides the following technical solution: A method for preparing an interface-adherent potassium ion gel electrolyte comprises the following steps: S1, adding azobisisobutyronitrile to a potassium ion electrolyte and stirring evenly until dissolved to obtain an electrolyte precursor; S2, uniformly mixing butyl acrylate and methyl methacrylate to obtain a gel electrolyte polymer precursor; S3. The electrolyte precursor and the gel electrolyte polymer precursor are uniformly mixed and stirred to prepare a gel electrolyte precursor, and then the gel electrolyte precursor is placed in a mold for thermal polymerization to obtain an interface-adherent potassium ion gel electrolyte.

[0005] As a preferred embodiment of the method for preparing an interface-adhered potassium ion gel electrolyte according to the present invention, in step S1, the potassium ion electrolyte comprises a potassium salt and an organic solvent, the potassium salt is KFSI (potassium bis(fluorosulfonyl)imide), and the organic solvent is ethylene carbonate and diethyl carbonate.

[0006] As a preferred embodiment of the method for preparing an interface-adherent potassium ion gel electrolyte according to the present invention, in step S1, the amount of azobisisobutyronitrile added is 0.8-1.2 wt.% of the mass of the gel electrolyte polymer precursor.

[0007] As a preferred embodiment of the method for preparing an interface-adherent potassium ion gel electrolyte according to the present invention, wherein: in step S2, the mass ratio of butyl acrylate to methyl methacrylate is 1:(5.98-6.02).

[0008] As a preferred embodiment of the method for preparing an interface-adherent potassium ion gel electrolyte according to the present invention, wherein: in the step S3, the mass ratio of the electrolyte precursor to the electrolyte polymer precursor is (5-5.03):(2.97-3).

[0009] As a preferred embodiment of the method for preparing an interface-adherent potassium ion gel electrolyte according to the present invention, wherein: in step S3, the mixing and stirring time is ≥10 min.

[0010] As a preferred embodiment of the method for preparing an interface-adherent potassium ion gel electrolyte according to the present invention, wherein: in step S3, the thermal polymerization temperature is ≥40°C.

[0011] As a preferred embodiment of the method for preparing an interface-adhered potassium ion gel electrolyte according to the present invention, wherein: in the step S3, the thermal polymerization time is ≥ 6 h.

[0012] According to another aspect of the present invention, the present invention provides the following technical solution: An interface-adherent potassium ion gel electrolyte is prepared by adopting the preparation method of the interface-adherent potassium ion gel electrolyte.

[0013] A potassium ion battery is assembled by placing the above-mentioned interface-adherent potassium ion gel electrolyte between a positive electrode sheet and a negative electrode sheet.

[0014] As a preferred embodiment of the potassium ion battery described in the present invention, the active material of the positive electrode sheet is 3,4,9,10-perylenetetracarboxylic dianhydride; and the negative electrode sheet is a potassium metal sheet.

[0015] As a preferred embodiment of the potassium ion battery described in the present invention, the potassium ion battery is a button battery.

[0016] The beneficial effects of the present invention are as follows: The present invention provides an interface-adhesive potassium ion gel electrolyte and a preparation method thereof, wherein azobisisobutyronitrile is added to a potassium ion electrolyte and stirred evenly until dissolved to obtain an electrolyte precursor; butyl acrylate and methyl methacrylate are evenly mixed to obtain a gel electrolyte polymer precursor; the electrolyte precursor and the gel electrolyte polymer precursor are evenly mixed and stirred to prepare a gel electrolyte precursor, and then the gel electrolyte precursor is placed in a mold for thermal polymerization to obtain an interface-adhesive potassium ion gel electrolyte. The present invention has a short production cycle, low cost, and simple operation. The prepared interface-adhesive potassium ion gel electrolyte has good interface adhesion, potassium metal affinity, and ion transport performance, and can be widely used in the field of potassium ion batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0018] Figure 1 This is a SEM surface photograph of the interfacially adhered potassium ion gel electrolyte prepared in Example 1 of the present invention.

[0019] Figure 2 The charge and discharge curves of the interfacially adhered potassium ion gel electrolyte prepared in Example 1 of the present invention when used in a potassium ion battery.

[0020] Figure 3 This is a cycle curve of the interfacially adhered potassium ion gel electrolyte prepared in Example 1 of the present invention when used in a potassium ion battery.

[0021] Figure 4 This is the charge and discharge curve of the liquid electrolyte of Comparative Example 1 when used in a potassium ion battery.

[0022] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0023] The following will be described clearly and completely in conjunction with the technical solutions in the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] The main purpose of the present invention is to provide an interface-adherent potassium ion gel electrolyte and a preparation method thereof, which has the following advantages: 1) The preparation method of the present invention is simple, has a short production cycle and is easy to operate.

[0025] 2) The interfacial adhesion gel electrolyte prepared by the present invention effectively prevents the electrolyte leakage problem existing in liquid potassium ion batteries. Based on the good interfacial adhesion properties of the prepared gel electrolyte, the interfacial stability between the electrolyte and potassium metal is enhanced, and the generation of dead potassium is effectively inhibited.

[0026] 3) The present invention is the first to prepare a potassium ion gel electrolyte with interfacial adhesion properties by copolymerizing soft and hard organic polymer monomers (soft monomer butyl acrylate and hard monomer methyl methacrylate).

[0027] The technical solution of the present invention is further described below in conjunction with specific embodiments.

[0028] Example 1 A method for preparing an interface-adherent potassium ion gel electrolyte comprises the following steps: S1. Add 0.03 g of azobisisobutyronitrile to 5 g of potassium ion electrolyte and stir until dissolved to obtain an electrolyte precursor; S2, uniformly mixing 0.428 g of butyl acrylate and 2.571 g of methyl methacrylate to obtain a gel electrolyte polymer precursor; S3. The electrolyte precursor and the gel electrolyte polymer precursor are uniformly mixed and stirred for 30 minutes to prepare a gel electrolyte precursor, and then the gel electrolyte precursor is placed in a mold and thermally polymerized at 40° C. for 6 hours to obtain an interface-adhered potassium ion gel electrolyte.

[0029] The SEM surface photograph of the interfacially adhered potassium ion gel electrolyte prepared in this example is shown in FIG. Figure 1 As shown, the surface of the prepared gel electrolyte is smooth and free of particles, indicating that the polymerized electrolyte is uniform and transparent, which is more conducive to the adhesion of the electrode.

[0030] In a glove box, 3,4,9,10-perylenetetracarboxylic dianhydride was used as the positive electrode and potassium metal sheet was used as the negative electrode. The interface-adhered potassium ion gel electrolyte prepared as described in Example 1 was placed between the positive and negative electrodes to assemble a button cell. The assembled solid-state potassium ion battery was subjected to constant current charge and discharge tests on a Neware battery tester, with the current density set to 100 mA g ‑1 , the test voltage range is 1.5~3.5V, the charge and discharge curve is as follows Figure 2 As shown, the discharge capacity is 134 mAh g -1 The cycle curve is as follows Figure 3 As shown, the semi-solid-state battery assembled based on adhesion potassium ion gel can achieve 1000 stable cycles and exhibits excellent electrochemical performance.

[0031] Comparative Example 1 In order to intuitively show the effect of gel electrolyte and liquid electrolyte on the performance of potassium ion battery, a mixture of 1M KFSI in ethylene carbonate and diethyl carbonate was used as the electrolyte, and the same positive and negative electrodes as in Example 1 were used. The assembled liquid potassium ion battery was subjected to constant current charge and discharge test on a Neware battery tester, and the current density was set to 100 mAg -1 , the test voltage range is 1.5~3.5V, the charge and discharge curve is as follows Figure 4 As shown. The discharge capacity is 127 mAh g -1 , and exhibits greater polarization.

[0032] The present invention adds azobisisobutyronitrile to a potassium ion electrolyte and stirs it evenly until it dissolves to obtain an electrolyte precursor; butyl acrylate and methyl methacrylate are evenly mixed to obtain a gel electrolyte polymer precursor; the electrolyte precursor and the gel electrolyte polymer precursor are evenly mixed and stirred to prepare a gel electrolyte precursor, and then the gel electrolyte precursor is placed in a mold for thermal polymerization to obtain an interface-adherent potassium ion gel electrolyte. The present invention has a short production cycle, low cost, and simple operation. The prepared interface-adherent potassium ion gel electrolyte has good interface adhesion, potassium metal affinity, and ion transport performance, and can be widely used in the field of potassium ion batteries.

[0033] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for preparing an interface-adherent potassium ion gel electrolyte, characterized in that: The steps include: S1, adding azobisisobutyronitrile to a potassium ion electrolyte and stirring evenly until dissolved to obtain an electrolyte precursor; S2, uniformly mixing butyl acrylate and methyl methacrylate to obtain a gel electrolyte polymer precursor; S3. The electrolyte precursor and the gel electrolyte polymer precursor are uniformly mixed and stirred to prepare a gel electrolyte precursor, and then the gel electrolyte precursor is placed in a mold for thermal polymerization to obtain an interface-adherent potassium ion gel electrolyte.

2. The method for preparing the interfacially adhered potassium ion gel electrolyte according to claim 1, wherein: In the step S1, the potassium ion electrolyte includes potassium salt and an organic solvent, the potassium salt is KFSI, and the organic solvent is ethylene carbonate and diethyl carbonate.

3. The method for preparing the interfacially adhered potassium ion gel electrolyte according to claim 1, characterized in that: In the step S1, the amount of azobisisobutyronitrile added is 0.8-1.2 wt.% of the mass of the gel electrolyte polymer precursor.

4. The method for preparing the interfacially adhered potassium ion gel electrolyte according to claim 1, wherein: In the step S2, the mass ratio of butyl acrylate to methyl methacrylate is 1:(5.98-6.02).

5. The method for preparing the interfacially adhered potassium ion gel electrolyte according to claim 1, characterized in that: In the step S3, the mass ratio of the electrolyte precursor to the electrolyte polymer precursor is (5-5.03):(2.97-3).

6. The method for preparing the interfacially adhered potassium ion gel electrolyte according to claim 1, characterized in that: In step S3, the mixing and stirring time is ≥10 min.

7. The method for preparing the interfacially adhered potassium ion gel electrolyte according to claim 1, characterized in that: In the step S3, the thermal polymerization temperature is ≥40°C.

8. The method for preparing the interfacially adhered potassium ion gel electrolyte according to claim 1, characterized in that: In the step S3, the thermal polymerization time is ≥ 6 hours.

9. An interface-adhered potassium ion gel electrolyte, characterized in that: The electrolyte is prepared by the method for preparing the interfacially adhered potassium ion gel electrolyte according to any one of claims 1 to 8.

10. A potassium ion battery, characterized in that: The interfacially adhered potassium ion gel electrolyte of claim 9 is assembled between a positive electrode sheet and a negative electrode sheet.

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